Ok BMW, this was pretty cool of you to do at the NAIAS (North American International Auto Show). Say hello to the S55B30, the motor that will be powering the upcoming F80 M3 and F82 M4. BMW already showed many of these details in a press release on the engine last year but real life photos of a motor that will be a staple in BMW tuning for years to come and specifications never hurt. As a reminder, the 3.0 liter direct injected twin turbo inline-6 has 430 horsepower and 406 pound-feet of torque (more than the previously reported 369).

The engine is also 22 pounds lighter than the S65 V8 and this is with fluids. The total engine weight is 452 pounds. The engine also revs to 7600 rpm. The compression ratio is a fairly high 10.2:1 and the same as the N55 inline-6 that sees duty in the 335i.

It is interesting to note that the bore and stroke are 84.0mm and 89.6mm respectively. Compare this to the bore and stroke of the N55 inline-6 which is at 84.0mm and 89.6mm. The N55 and S55 share the exact same 2,979 cc displacement and same bore x stroke.

BMW designed the S55 undersquare like the N55 and N54. This allows for greater torque down low in the rev range. The S55 develops its peak torque as early as 1850 rpm and maintains it until 5500 rpm meaning the oversquare design has not hurt the low end much (although the N55 hits peak torque earlier) and BMW has done a good job balancing high RPM power and low end punch.

BMW's turbochargers are produced by Honeywell and generate 1.25 bar (18.12 psi) of boost. Will there be room to push the turbos past this level? Most certainly. The question will be by how much.

The downsides? The fuel tank is only 15.8 gallons. Why BMW continues to give their M3's such small fuel tanks is anyone's guess.

Good luck trying to upgrade that AWIC or even doing a turbo upgrade on this thing. Looks like Dinan will more likely be the first vendor to come out with a AWIC upgrade for the S55 though, pretty sure about that. However, for a little bigger core, they are going to rape you like hell on the price tag.

Already know what the HPFP looks like. Just look at the latest N55 pump. They converted the housing that used the rotational pump so it would accept a traditional style cam driven pump. All those parts are available right now if you want to give them a shot, we almost did it, but decided against it.

Good luck trying to upgrade that AWIC or even doing a turbo upgrade on this thing. Looks like Dinan will more likely be the first vendor to come out with a AWIC upgrade for the S55 though, pretty sure about that. However, for a little bigger core, they are going to rape you like hell on the price tag.

I think the M235i will be mush more mod friendly than the M3/M4

Why do you say that? AWIC's are super common and easy to upgrade we have been running them for decades, spearco prob has a much better flowing core that will fit right in there, get some better flowing ends either cast or fabricated and you have an upgraded AWIC.

has anyone seen anything more specific on the internal metalurgy specifications? Are pistons/rods/crank all forged? Also, never understood why so many oems put plastic end tanks on intercoolers. I wasnt expecting an air to water intercooler though.

Good luck trying to upgrade that AWIC or even doing a turbo upgrade on this thing. Looks like Dinan will more likely be the first vendor to come out with a AWIC upgrade for the S55 though, pretty sure about that. However, for a little bigger core, they are going to rape you like hell on the price tag.

I think the M235i will be mush more mod friendly than the M3/M4

I dont think that upgrade will be a bad one. You can get almost any size awic now days and BMW has done the hard part of integrating it into the coolant system.

I dont think that upgrade will be a bad one. You can get almost any size awic now days and BMW has done the hard part of integrating it into the coolant system.

I think running the engine coolant through it is also part of the what needs to be changed, these engines run very high water temps, and getting rid of that and running a dedicated coolant supply for the AWIC will net much lower IAT's. What good is running 210 degree water through a heat exchanger thats trying to cool off a less than 200 degree Air temps. I think there was a MB platform running an AWIC and this was part of the upgrade, getting it out of the cooling system loop.

Edit: The more I look the more it appears BMW was smarter than running the coolant through the AWIC. That coolant tank the IC is connected to near the firewall looks much too small for the entire engine, the IC system most likely has its own coolant system, including heat exchanger, and pump.

I think running the engine coolant through it is also part of the what needs to be changed, these engines run very high water temps, and getting rid of that and running a dedicated coolant supply for the AWIC will net much lower IAT's. What good is running 210 degree water through a heat exchanger thats trying to cool off a less than 200 degree Air temps. I think there was a MB platform running an AWIC and this was part of the upgrade, getting it out of the cooling system loop.

Edit: The more I look the more it appears BMW was smarter than running the coolant through the AWIC. That coolant tank the IC is connected to near the firewall looks much too small for the entire engine, the IC system most likely has its own coolant system, including heat exchanger, and pump.

Yes, all fo the 32 and 55 series Kompressor motors circulate the same engine coolant throught the AWIC. However, they did at least have a separate heat exchanger that the water flowed through before going to the AWIC (from the factory). That brought the water temp way down compared to the ECT.

On my C32 AMG I took that a step further. I moved my battery to the trunk and replaced it with a water tank that mounted in the battery tray, then separated the water circuit. It was made to fit an 03-04 Cobra, but I adapted it to work.

has anyone seen anything more specific on the internal metalurgy specifications? Are pistons/rods/crank all forged? Also, never understood why so many oems put plastic end tanks on intercoolers. I wasnt expecting an air to water intercooler though.

Watch BMW fixes absolutely everything that anyone could possibly want with the direct injected turbo motors and gives the turbos plenty of headroom but makes the ECU uncrackable. It would be such a cruel joke.

No such thing. All it takes is talent, or the money to hire it. And I'm willing to bet there will be plenty of money in that market.

Interesting to note, it looks like the wastegates are purely electronic. No vacuum connections. Aside from allowing BMW complete control over when and how much they open, I assume it will also allow them more data on wastegate performance and mod detection.